I don’t think there’s an issue doing full bleed.
Most people who look at your portfolio will probably look at it on screen if you are e-mailing it out, and if they do print it they won’t be critiquing your margins knowing that they just printed it. Just keep it to a regular paper size (IE don’t do full bleed 8x8" square if you expect someone to print it themselves.)
There are some of the more professional book binding sites out there now that can do a properly trimmed full bleed bound portfolio for you if you’ve got the money.